Economical development of oil and gas reserves in Kiowa and Washita counties of Southwestern Oklahoma requires drilling complex structural features with faulted formations and highly dipping beds.To address these challenges, many operators employ packed hole and/or conventional directional motor assemblies to keep inclination to a minimum drilling the production section.While this type of bottom hole assembly has improved directional control, in many cases it still leads to unacceptable angle building tendencies (ie bit walk) and high dogleg severity.This type of BHA has also led to poor vertical hole quality resulting in additional directional issues in subsequent hole sections.In addition, the conventional directional assembly increases well costs due to multiple deviation correction runs with different BHA configurations resulting in more flat time, lower cumulative bit penetration rate, and more bits/runs per hole section.

To reduce drilling costs and maximize production in the region, a service company conducted a detailed analysis of drilling performance, mud logs and wireline data from offset wells. The in-depth study helped engineers identify key problems limiting drilling performance.This led the operator to set new objectives for the production hole section of achieving the highest possible rate of penetration while maintaining a near-vertical wellbore.An implementation strategy was outlined that had two main components including a vertical deviation control system and new PDC bit technology.

This strategy has been implemented to drill 17 wells with excellent results (Operator had previously drilled over 55 wells in the area with the old BHA).The new BHA combination has minimized directional deviation (inclination) and reduced dogleg severity.It has also reduced torque and drag helping deliver a smooth, high quality wellbore and has totally eliminated costly correction runs and increased efficiency and quality of cementing operations.This has allowed the operator to log and set tubulars without incident.

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